The short arm of rye (Secale cereal L.) chromosome 1 (1RS), beside of being part of the rye genome, is present in many hundred wheat cultivars as the 1RS.1BL or 1RS.1DL wheat-rye translocation. in the present work the distribution of the wheat-rye translocation 1RS.1BL was studied in 28 winter and spring wheat varieties from iran of which 9 have a donor of 1RS.1DL translocation and 18 randomly selected varieties without a known source of 1RS.1BL in their pedigree. the presence of the translocation was verified in 5 vasrieties using chromosome staining and genomic in situ hybridization analysis.